The incidence of lung cancer has been rising over the last half century, although the rate has decreased somewhat over the last decade because of increased publicity about the health risks. The American Cancer Society estimates the number of new cases in 2009 to exceed 219,000. Lung cancer is the leading cause of cancer deaths in the United States among both men and women, expected to reach 159,000 in 2009, claiming more lives than colon, prostate and breast cancer combined.i 
Non-small cell lung cancer (NSCLC) is the most commonly diagnosed form of the disease, affecting 4 out of 5 patients. In United States, ˜23% of patients present with early-stage (T1, T2) disease.ii In most cases, early stage NSCLC can be treated successfully with surgery if the cancer has not spread beyond the chest. Surgical resection is the definitive treatment and lobectomy is the procedure of choice.iii, iv, v Lobectomy is the most common type of lung cancer surgery, involving removal of an entire lobe of one lung. For these early stage NSCLC patients, lobectomy yields a 5-year survival rate of 65-77%. Locoregional recurrence occurs in 28% of T1N0 tumors submitted to thoractomy, with the highest initial failure rates detected in the ipsilateral hemithorax.vi, vii Unfortunately, some patients with this disease are poor candidates for lobectomy due to poor pulmonary health or other medical issues.
Stage I NSCLC patients with compromised cardiopulmonary status may undergo limited surgical resections in an attempt at lung preservation while achieving adequate resection margins.viii However, lesser resections have been associated with an increased risk of local recurrence, even for small peripheral tumors.ix Nonetheless, limited resection is viewed as an acceptable alternative for patients with poor physiologic reserve or of advanced age.x, xi 
Though sublobar resection alone is associated with an increased incidence of post-operative disease recurrence, it is still advocated for high-risk patients in the absence of a good alternative. External beam radiation therapy has been used successfully to reduce the risk of local recurrence in these compromised patients.xii However, external beam radiation therapy further reduces pulmonary function because it generally requires the beam to pass through normal lung tissue to reach the target lesion. Some studies suggest that adding brachytherapy to the regimen can make a dramatic difference in outcomes.
Intraoperative brachytherapy has been shown to be an effective therapeutic modality for patients unable to undergo a surgical lobectomy; it is an alternative to external beam irradiation for patients who cannot tolerate further loss of lung function.xiii, xiv 
The use of brachytherapy has been shown in several studies to have a clinical benefit for compromised lung cancer patients for whom more traditional surgical procedures, such as a lobectomy, are not an option. This is now the subject of a NIH-sponsored Phase III Clinical trial.xv 
These candidate patients would undergo limited (sublobar) surgical resection (wedge resection) in an attempt at lung preservation while achieving adequate resection margins, followed by brachytherapy. Currently, brachytherapy is performed using 125Iodine seeds delivered at the time of surgery. Seeds have been deployed by a variety of techniques such as manually suturing stranded seeds,xvi manually delivering loose seeds via a Mick® applicator,xvii thoracoscopic placement of vicryl mesh imbedded with 125Iodine radioactive seeds,xviii and seed placement in the wedge resection margin using the da Vinci robotic system.xix 
The problem with all of these techniques is the difficulty in precisely delivering the brachytherapy seeds intraoperatively to achieve the proper dose distribution and minimizing the radiation dose to the clinicians performing the procedure.
When removing non-small cell lung cancers, the most prevalent form of lung cancer, conventional staples are typically used for the procedure. Moreover, the use of radioactive sources are placed near the cancer site to provide a mode of treatment. In this regard, U.S. Pat. Nos. 7,604,586 and 7,972,260 disclose one mode of treatment using staples containing a radioactive material and the attachment of these staples near the surgical resection. Reference may also be made to the aforementioned patents for background discussions pertaining to brachytherapy procedures.
Accordingly, there is a need for a staple delivery applicator having means for the accurate placement of radioactive staples at surgical sites.
Another object of the present invention to provide an apparatus or instrument for incorporating a radioactive source into or with a surgical procedure means such as a surgical staple so that the radioactive source can be positioned substantially concurrently with the application of the surgical tissue securing means.
Still another object of the present invention is to provide a brachytherapy source-delivery system and instrument that facilitates the precise placement of brachytherapy sources relative to a surgical margin, assures the seeds remain fixed in their precise position for the duration of the treatment, overcomes the technical difficulties of manipulating the seeds through a narrow surgical incision inherent in minimally invasive procedures, and at the same time reduces the radiation dose to the clinicians.
A further object of the present invention is to provide a means for irradiating cancer tissue with the use of staples in lung, colorectal and gynecological cancers, for example.
It is another object of the present invention to provide an effective therapeutic modality for patients unable to undergo a surgical lobectomy; it is an alternative to external beam irradiation for patients who cannot tolerate further loss of lung function.
It is a further object of the present invention to provide a means to precisely deliver the brachytherapy sources intraoperatively to achieve the proper dose distribution and minimizing the radiation dose to the clinicians performing the procedure.
It is still a further object of the present invention to provide a means for precise placement of brachytherapy sources relative to the surgical margin, assuring the sources remain fixed in their precise positions for the duration of the treatment, overcoming the technical difficulties of manipulating the sources through the narrow surgical incision, and reducing the radiation dose to the clinicians.
It is yet a further object of the present invention to provide a delivery device having better shielding than the existing stapler cartridges, thereby providing greater safety to the physician and other operating room personnel.
It is yet a further object of the present invention to provide a device that reduces the possibility of mis-locating sources by reducing and/or by limiting the number of potential source positions to only dosimetrically useful positions, rather than all staple positions, and further locating the sources nearer to the center of the treatment volume rather than at its edge.